Rolling bearing

ABSTRACT

In a rolling bearing including a cage arranged in an annular space between an outer ring and an inner ring, a plurality of rolling elements held by the cage, and a solid lubricating agent provided in the cage, the cage has a plurality of rolling element receiving pockets in a circumferential direction, and has recess portions between the rolling element receiving pockets in a circumferential direction, and each of the rolling elements is received in each of the rolling element receiving pockets. The solid lubricating agent is attached to the recess portions in such a manner as to be in a slidable contact with a rolling element raceway surface.

TECHNICAL FIELD

The present invention relates to a rolling bearing.

BACKGROUND ART

In a rolling bearing used under a high temperature and a high pressure,a raceway surface of a rolling element can not be kept by a lubricatingagent, such as a grease, or the like. Accordingly, there is a case thata cage holding the rolling element itself is formed by the lubricatingagent. As this kind of lubricating agent, for example, there is employeda graphite, which is fragile but is excellent in a lubricating property.In the rolling bearing mentioned above, there is a case that the rollingelement slips against the raceway surfaces of inner and outer rings anda lead-lag is generated, whereby a compression force and a tensile forceare applied to the cage. In the case mentioned above, since the cage isformed by the fragile lubricating agent, such as the graphite, or thelike, there is a risk that a life of the cage becomes short. There is acase that a spacer formed by the lubricating agent, such as thegraphite, or the like is used in place of the cage mentioned above. Inthis case, there is also a risk that the life of the cage becomes shortin the same manner as mentioned above.

DISCLOSURE OF THE INVENTION

A rolling bearing, in accordance with the present invention includes apair of bearing rings arranged in an inner side and an outer side in adiametrical direction, a cage arranged in an annular space between boththe bearing rings, a plurality of roller elements held by the cage, anda solid lubricating agent provided in the cage, the cage has a pluralityof rolling element receiving pockets in a circumferential direction andhas recess portions between the rolling element receiving pockets in thecircumferential direction, the rolling elements are received in therespective rolling element receiving pockets, and the solid lubricatingagent is attached to the recess portions in such a manner as to be in aslidable contact with a rolling element raceway surface.

In the structure mentioned above, since the solid lubricating agent isattached to the engaging recess portions of the cage, the solidlubricating agent revolves around an axis, in accordance with a rotationof the cage around the axis, and the solid lubricating agent is slidablyin contact with the raceway surface so as to lubricate.

In accordance with a preferable mode of the present invention, the solidlubricating agent has a first lubricating portion, which is slidably incontact with a raceway surface of one bearing ring, and a secondlubricating portion, which is slidably in contact with a guide surfacein a shoulder portion of the one bearing ring. In accordance with thismode, when the cage rotates around the axis, the solid lubricating agentmoves in a state, in which the solid lubricating agent is attaché to theengaging recess portion of the cage, the first lubricating portion ofthe solid lubricating agent is slidably in contact with the racewaysurface of the bearing ring so as to lubricate the raceway surface, andthe second lubricating portion is slidably in contact with the guidesurface in the shoulder portion of the bearing ring so as to lubricatethe guide surface.

In accordance with a further preferable mode of the present invention,the solid lubricating agent is attached to the recess portion in such amanner as to slightly move in a peripheral direction with respect to thecage. In accordance with this mode, when the cage starts rotating, thesolid lubricating agent revolves around the axis slightly behind thecage, and lubricates the raceway surface or the guide surface in theshoulder portion of the bearing ring. Even if the lead-lag of therolling element is generated, no compression force is applied to thesolid lubricating agent, and the solid lubricating agent can beprevented from being broken down.

In accordance with a further preferable mode of the present invention,the solid lubricating agent is attached to the recess portion in such amanner as to be slidably in contact with the rolling element. Inaccordance with this mode, when the cage starts rotating, the solidlubricating agent revolves around the axis slightly behind the cage, andlubricates the raceway surface or the guide surface in the shoulderportion of the bearing ring, and the rolling surface of the rollingelement. Even if the lead-lag of the rolling element is generated, nocompression force is applied to the solid lubricating agent, and thesolid lubricating agent can be prevented from being broken down.

In accordance with a further preferable mode of the present invention,an inclined surface pressing the solid lubricating agent in adiametrical direction, in accordance with the rotating motion of thecage around the axis is provided in the recess portion. In accordancewith this mode, in the case that a height of the solid lubricating agentin the diametrical direction is reduced, in accordance with the use ofthe solid lubricating agent, the solid lubricating agent is pressed inthe diametrical direction by the inclined surface, in accordance withthe rotation of the cage, and the solid lubricating agent lubricates theraceway surface, or the guide surface in the shoulder portion of thebearing ring, and the rolling surface of the rolling element.

In this case, the bearing ring arranged in the outer side in thediametrical direction among the bearing rings mentioned above is notlimited to the annular shaped member and includes a housing or the like.Similarly, the bearing ring arranged in the inner side in thediametrical direction is not limited to the annular shaped member andincludes a solid axial body or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a whole of a rolling bearing, inaccordance with a best embodiment of the present invention;

FIG. 2 is a partly enlarged view of the rolling bearing;

FIG. 3 is an enlarged cross sectional view along a line X—X in FIG. 1;

FIG. 4 is an enlarged cross sectional view along a line Y—Y in FIG. 1;

FIG. 5 is an enlarged perspective view of the rolling bearing in apartly rupturing manner;

FIG. 6 is an enlarged perspective view of a solid lubricating agent ofthe rolling bearing;

FIG. 7 is a front elevational view of a whole of a rolling bearing, inaccordance with another embodiment of the present invention;

FIG. 8 is a partly enlarged view of the rolling bearing; and

FIG. 9 is an enlarged cross sectional view along a line Z—Z in FIG. 7.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 to 6 relates to a best embodiment, in accordance with thepresent invention. A description is given below of a rolling bearing, inaccordance with the best embodiment of the present invention. Withreference to these drawings, reference numeral 1 denotes a rollingbearing. The rolling bearing 1 has a structure of radial roller bearing(a cylindrical roller bearing), and is used, for example, in a machinetool, or the like. The roller bearing 1 is provided with an outer ring 2corresponding to one bearing ring arranged in an outer side in adiametrical direction, and an inner ring 4 corresponding to anotherbearing ring arranged in an inner side in the diametrical direction withrespect to the outer ring 2. The outer ring 2 and the inner ring 4 arearranged in a state, in which opposing surfaces thereof are opposed toeach other via an annular space 3 in the diametrical direction. Theroller bearing 1 further has a cage 5 arranged in the annular space 3,and a cylindrical roller 7 received in a rolling element receivingpocket 6 formed in the cage 5 at uniformly arranged positions in acircumferential direction. The rolling bearing 1 is of an outer ringguide type, in which the inner ring 4 is not rotated, the outer ring 2is freely rotated around an axis 8, and an outer peripheral surface ofthe cage 5 is guided along an inner peripheral surface of the outer ring2.

The outer ring 2 is provided with a groove portion 10 forming an outerring raceway surface 9 of the cylindrical roller 7 in an innerperipheral side thereof, and is provided with a collar portion 11 (ashoulder portion) for holding the cylindrical roller 7 in the axialdirection 8 in both sides of the groove portion 10 in the axialdirection 8. The inner ring 4 is provided with an inclined surface 12for assembling formed in both sides of the inner peripheral surface inthe axial direction 8. A portion between the inclined surfaces 12 isformed as an inner ring raceway surface 14 of the cylindrical roller 7.

The outer ring 2 and the inner ring 4 mentioned above are formed by abearing steel, such as a high speed tool steel, or the like (forexample, SKH4 is employed), and is titanium-coated so as to resist undera high temperature, for example, by TiN. The cylindrical roller 7 isformed by a ceramics. The ceramics is constituted by setting a siliconnitride (Si₃N₄) to a main component and adding an appropriate sinterassisting component. As the sinter assisting component, there isemployed an aluminum nitride (AlN), a titanium oxide (TiO₂), a spinel(MgAl₂O₄), or the like, in addition to an yttria (Y₂O₃) and an alumina(Al₂N₃).

The cage 5 is constituted by an annular portion 17 integrally formed bya first roller holding surface portion 15 holding the cylindrical roller7 by one side in the axial direction 8 and a holding portion 16 havingthe pocket 6, a second roller holding surface portion 18 holding thecylindrical roller 7 by another side in the axial direction 8, and aplurality of rivets 19 for integrally forming the annular portion 17 andthe second roller holding surface portion 18. The annular portion 17 andthe second roller holding surface portion 18 are integrally formed bycaulking both end portions in a state, in which the rivets 19 passthrough both the roller holding surface portions 15 and 18. The cage 5mentioned above is formed by a stainless bearing steel or a carbonsteel, for example, steel kinds SUS304, SUS316, SUS630, S25C areemployed. A coating of TiN mentioned above may be applied onto a surfaceof the cage 5.

There is provided a plurality of solid lubricating agents 20 forlubricating the outer ring raceway surface 9, the inner ring racewaysurface 14 and the collar portion 11, in accordance with a rotatingmotion of the cage 5 around the axis. The solid lubricating agent 20 hasa solid form, and is attached over engaging recess portions 21 formed inouter peripheral portions of both the holding surface portions 15 and18. The engaging recess portions 21 are formed at uniformly arrangedpositions of both the roller holding surface portions 15 and 18 in acircumferential direction. The engaging recess portions 21 are arrangedbetween the pockets 6 in the cage 5, in other words, positionscorresponding to portions between the rollers in the cage 5. Theengaging recess portion 21 has a bottom surface 22, and a pair ofinclined surface 13 inclined in such a manner as to expand toward anouter side in the diametrical direction from both sides of the bottomsurface 22 in a circumferential direction.

The solid lubricating agent 20 is integrally formed by a firstlubricating portion 23 detachably fitted to the groove portion 10 of theouter ring 2, and a second lubricating portion 24 bulging out to bothsides of the first lubricating portion 23 in the axial direction 8 so asto be loosely fitted to the engaging recess portion 21. The solidlubricating agent 20 is formed by a graphite. Alternatively, the solidlubricating agent 20 is formed by a laminated material, such as tungstendisulfide, molybdenum disulfide, or the like, a soft metal material,such as gold, silver, lead, or the like, and a polymer resin material,such as PTFE, polyimide, or the like.

An outer peripheral surface 230 of the first lubricating portion 23 isformed so as to have the same curvature as that of the outer ringraceway surface 9, and is slidably in contact with the outer ringraceway surface 9, in accordance with the rotation of the outer ring 2.A side surface 231 of the first lubricating portion 23 is slidably incontact with both wall surfaces of the groove portion 10, in accordancewith the rotation of the outer ring 2. An outer peripheral surface 240of the second lubricating portion 24 is formed so as to have the samecurvature as that of an inner peripheral surface of the collar portion11, and is slidably in contact with the inner peripheral surface of thecollar portion 11, in accordance with the rotation of the outer ring 2.A back surface 200 of the solid lubricating agent 20 (the firstlubricating portion 23 and the second lubricating portion 24) isslidably in contact with a rolling surface of the cylindrical roller 7in a downstream side of the solid lubricating agent 20 in a rotatingdirection at a time when the outer ring 2 is rotated. A height of thefirst lubricating portion 23 in a diametrical direction is approximatelyequal to a distance from the outer ring raceway surface 9 to an outerperipheral surface of the annular portion 17. A width of the firstlubricating portion 23 in an axial direction 8 is approximately equal toa distance between both the wall surfaces of the groove portion 10. Aheight of the second lubricating portion 24 in the diametrical directionis approximately equal to a distance from the bottom surface 22 of theengaging recess portion 21 to the inner peripheral surface of the collarportion 11 in the outer ring 2. A width of the entire solid lubricatingagent 20 in the axial direction 8 is slightly smaller than the width ofthe cage 5. A small clearance 25 is provided between the inclinedsurface 13 of the engaging recess portion 21 and the cylindrical roller7, and the back surface 200 of the solid lubricating agent 20 opposingto the inclined surface 13.

The rolling bearing 1 having the structure mentioned above is assembled,in accordance with the following procedures. (1) Scuffing the graphiteon both the wall surfaces of the outer ring raceway surface 9 and thegroove portion 10 in the outer ring 2, and the inner peripheral surfaceof the collar portion 11 (the guide surface of the cage 5). (2) Fittinga plurality of solid lubricating agents 20 to the groove portion 10 soas to hold them at the predetermined circumferential uniformly arrangedpositions. (3) Scuffing the graphite on both the side end surfaces ofthe cylinder roller 7 and attaching the cylindrical roller 7 between thesolid lubricating agents 20 so as to hold them. (4) Attaching theannular portion 17 from one side in the axial direction 8 in such amanner as to align the pocket 6 with the position of the cylindricalroller 7 and position the engaging recess portion 21 to the solidlubricating agent 20. (5) Attaching the second roller holding surfaceportion 18 from another side in the axial direction 8 in such a manneras to position the engaging recess portion 21 to the solid lubricatingagent 20. (6) Inserting a plurality of rivets 19 to the annular portion17 and the second roller holding surface portion 18 and caulking bothend portions thereof. (7) Assembling the inner ring 4 after scuffing thegraphite on the inner ring raceway surface 14 of the inner ring 4. Therolling bearing 1 is assembled, in accordance with the above steps.

In the rolling bearing 1, when the outer ring 2 is rotated around theaxis 8, the cage 5 is rotated around the axis 8, in accordance with therolling of the cylindrical roller 7. Each of the solid lubricatingagents 20 revolves around the axis 8 accordingly. At this time, theouter peripheral surface 230 of the first lubricating portion 23 in eachof the solid lubricating agents 20 is slidably in contact with the outerring raceway surface 9 or slides on the outer ring raceway surface 9 soas to lubricate the outer ring raceway surface 9. Further, the sidesurface 231 of the first lubricating portion 23 is slidably in contactwith both the wall surfaces of the groove portion 10 so as to lubricatethe groove portion 10. The outer peripheral surface 240 of the secondlubricating portion 24 is slidably in contact with the inner peripheralsurface of the collar portion 11 corresponding to the guide surface ofthe cage 5 so as to lubricate the inner peripheral surface of the collarportion 11.

At this time, since the slight clearance 25 is formed between theinclined surface 13 of the engaging recess portion 21 and the backsurface 200 of the solid lubricating agent 20 opposing to the inclinedsurface 13, the solid lubricating agent 20 starts a revolving motionbehind the rotation of the cage 5 by a degree of the clearance 25.Accordingly, the back surface 200 of the solid lubricating agent 20 isslidably in contact with the rolling surface (the front surface) of thecylindrical roller 7 in the downstream side of the solid lubricatingagent 20 in the rotating direction so as to lubricate the rollingsurface of the cylindrical roller 7. When the first lubricating portion23 of the sold lubricating agent 20 lubricates the outer ring racewaysurface 9, and the back surface 200 of the solid lubricating agent 20lubricates the raceway surface of the cylindrical roller 7, the innerring raceway surface 14 is lubricated.

In the case that the lead-lag is generated in a part of a plurality ofcylindrical rollers 7, in accordance with the rotation of the outer ring8 around the axis 8, the cylindrical roller 7 is brought into contactwith the peripheral wall of the pocket 6 in the cage 5, so that there isa case that the cage 5 is exposed to a compression force in theperipheral direction particularly with respect to an adjacentcylindrical roller 7.

However, as mentioned above, since the slight clearance 25 is providedbetween the inclined surface 13 of the engaging recess portion 21 andthe back surface 200 of the solid lubricating agent 20 opposing to theinclined surface 13, no compression force is applied to the solidlubricating agent 20. Accordingly, even if the lead-lag is generated ina part of the cylindrical rollers 7, a phenomenon that the solidlubricating agent 20 is broken away due to the lead-lag can beprevented.

Further, when the solid lubricating agent 20 revolves around the axis 8and is slidably in contact with both the wall surfaces of the grooveportion 10 and the inner peripheral surface of the collar portion 11 soas to lubricate, the height of the solid lubricating agent 20 in thediametrical direction is reduced step by step. However, since theinclined surface 13 is formed in the engaging recess portion 21, thesolid lubricating agent 20 is pressed to the outer side in thediametrical direction by the inclined surface 13, in accordance with therotation of the cage 5 around the axis 8. Accordingly, even in the casethat the height of the solid lubricating agent 20 in the diametricaldirection is reduced, in accordance with the use, it is possible to keepthe operation that the solid lubricating agent 20 is slidably in contactwith both the wall surfaces of the groove portion 10 and the innerperipheral surface of the collar portion 11 so as to lubricate, inaccordance with the rotation of the cage 5 around the axis 8.

In particular, in the case of applying a rolling bearing correspondingto model number NU206 (inner diameter 30 mm, outer diameter 62 mm, width16 mm), as the rolling bearing 1, in accordance with the presentinvention to a machine tool under a working environment comprising aworking temperature: 550° C., a radial load: 1.2 ton and a rotationnumber: 300 rpm, the cylindrical roller 7 and the solid lubricatingagent 20 stands against the working over eight hours without breakingaway.

In accordance with the structure mentioned above, the clearance 25 isprovided between the inclined surface 13 of the engaging recess portion21 in the cage 5, and the back surface 200 (the opposing surface) of thesolid lubricating agent 20 opposing to the inclined surface 13. Further,since the compression force caused by the lead-lag of the cylindricalroller 7 is supported by the cage 5, the compression force can beprevented from being applied to the solid lubricating agent 20.Accordingly, the solid lubricating agent 20 can be prevented from beingbroken away due to the lead-lag of the cylindrical roller 7 so as tolubricate the necessary surface.

Further, since the inclined surface 13 is formed in the engaging recessportion 21 of the cage 5, the solid lubricating agent 20 is pressed tothe outer side in the diametrical direction by the inclined surface 13,in accordance with the rotation of the cage 5 around the axis 8 even inthe case that the height of the solid lubricating agent 20 in thediametrical direction is reduced in correspondence to the working.Accordingly, it is possible to maintain the operation that the solidlubricating agent 20 is slidably in contact with both the wall surfacesof the groove portion 10 and the inner peripheral surface of the collarportion 11 so as to lubricate, for a long period (a long time) evenunder a severe working environment.

A description is given of another embodiment, in accordance with thepresent invention with reference to FIGS. 7 to 9. A rolling bearing, inaccordance with this embodiment is of an inner ring guide type. FIG. 7is a front elevational view of a whole of the rolling bearing, FIG. 8 isa partly enlarged view of the rolling bearing, and FIG. 9 is an enlargedcross sectional view along a line Z—Z in FIG. 7. In these figures,reference numeral 30 denotes a rolling bearing. The rolling bearing 30has an outer ring 31, an inner ring 33 arranged in an inner side of theouter ring 31 via an annular space 32, a cage 34 arranged in the annularspace 32, and a cylindrical roller 36 receives in a pocket 35 formed inthe cage 34 at uniformly arranged positions in a circumferentialdirection.

As illustrated, the outer ring 31 is provided with an outer ring racewaysurface 37 of the cylindrical roller 36 formed in an inner peripheralside thereof. An inclined surface 39 for assembling is formed in bothsides of the outer ring raceway surface 37 in a direction of an axis 38.

A groove portion 42 forming an inner ring raceway surface 41 of thecylindrical roller 36 is formed in an outer peripheral surface of theinner ring 33, and a collar portion 43 for holding the cylindricalroller 36 in the direction of the axis 38 is formed in both sides of thegroove portion 42 in the direction of the axis 38.

The structure of the cage 34 is the same as that of the embodimentmentioned above. In other words, the cage 34 is constituted by anannular portion 46 integrally forming a holding portion 45 having afirst roller holding surface portion 44 and the pocket 35, a secondroller holding surface portion 47, and a plurality of rivets 48. In thiscase, the rivets 48 are positioned in an outer side in a diametricaldirection in comparison to the first embodiment.

There are provided a plurality of solid lubricating agents 49 forlubricating the inner ring raceway surface 41, the outer ring racewaysurface 37 and the collar portion 43, in accordance with the rotation ofthe cage 34 around the axis 38. These solid lubricating agents 49 arerespectively attached to a plurality of engaging recess portions 50formed in inner peripheral portions of both the holding surface portions44 and 47 of the cage 34. The engaging recess portions 50 are arrangedbetween the pockets 35 in both the roller holding surface portions 44and 47, in other words, positions corresponding to portions between therollers in the cage 34. The engaging recess portion 50 in both theholding surface portions 44 and 47 has a bottom surface 51 in an outerside in the diametrical direction, and an inclined surface 40 inclinedin such a manner as to expand toward an inner side in the diametricaldirection from both sides of the bottom surface 51 in a circumferentialdirection, and is formed in an approximately trapezoidal shape in afront view.

The solid lubricating agent 49 is integrally formed by a firstlubricating portion 52 detachably fitted to the groove portion 42 of theinner ring 33, and a second lubricating portion 53 bulging out to bothsides of the first lubricating portion 52 in the direction of the axis38 so as to be loosely fitted to the engaging recess portion 50.

An inner peripheral surface 520, which is slidably in contact with theinner ring raceway surface 41, in accordance with the rotation of theinner ring 33 and has the same curvature as that of the inner ringraceway surface 41 is formed in the first lubricating portion 52. A sidesurface 521, which is slidably in contact with both wall surfaces of thegroove portion 42, in accordance with the rotation of the inner ring 33is formed in the first lubricating portion 52. An inner peripheralsurface 530, which is formed so as to have the same curvature as that ofan outer peripheral surface of the collar portion 43, and is slidably incontact with the outer peripheral surface of the collar portion 43, inaccordance with the rotation of the inner ring 33 is formed in thesecond lubricating portion 53. A back surface 490, which is slidably incontact with a rolling surface of the cylindrical roller 36 in adownstream side of the solid lubricating agent 49 in a rotatingdirection at a time when the inner ring 33 is rotated is formed in thesolid lubricating agent 49 (the first lubricating portion 52 and thesecond lubricating portion 53).

A height of the first lubricating portion 52 in a diametrical directionis formed at an approximately equal distance to a distance from theinner ring raceway surface 41 to an inner peripheral surface of theannular portion 46. A width of the first lubricating portion 52 in thedirection of the axis 38 is formed at an approximately equal width to adistance between both the wall surfaces of the groove portion 42.

A height of the second lubricating portion 53 in the diametricaldirection is formed so as to be approximately equal to a distance fromthe bottom surface 51 of the engaging recess portion 50 to the outerperipheral surface of the collar portion 43. A small clearance 54 isprovided between the inclined surface 40 of the engaging recess portion50 and the back surface 490 of the solid lubricating agent 49 opposingto the inclined surface 40. In this case, a width of the entire solidlubricating agent 49 in the direction of the axis 38 is set to beslightly smaller than the width of the cage 34. Further, the outer ring31, the inner ring 33, the cage 34 and the solid lubricating agent 49are respectively formed by the same material as those in the firstembodiment mentioned above.

Next, a description is given of an assembling procedures of the rollingbearing 30 having the structure mentioned above. (1) Scuffing thegraphite on the inner ring raceways surface 41 of the inner ring 33,both the wall surfaces of the groove portion 42, and the outerperipheral surface (the guide surface of the cage 34). (2) Fitting aplurality of solid lubricating agents 49 to the groove portion 42 so asto hold them at the predetermined circumferential uniformly arrangedpositions. (3) Scuffing the graphite on both the side end surfaces ofthe cylinder roller 36 and attaching the cylindrical roller 36 betweenthe solid lubricating agents 49 so as to hold them. (4) Attaching theannular portion 46 from one side in the direction of the axis 38 in sucha manner as to align the pocket 35 with the position of the cylindricalroller 36 and position the engaging recess portion 50 to the solidlubricating agent 49. (5) Attaching the second roller holding surfaceportion 47 from another side in the direction of the axis 38 in such amanner as to position the engaging recess portion 50 to the solidlubricating agent 49. (6) Inserting a plurality of rivets 48 to theannular portion 46 and the second roller holding surface portion 47 andcaulking both end portions thereof. (7) Assembling the outer ring 31after scuffing the graphite on the outer ring raceway surface 37 of theouter ring 31. The rolling bearing 30 is assembled, in accordance withthe above steps.

In the rolling bearing 30 having the structure mentioned above, when theinner ring 33 is rotated around the axis 38, the cage 34 is rotatedaround the axis 38, in accordance with the rolling of the cylindricalroller 36. The solid lubricating agents 49 revolve around the axis 38accordingly. At this time, the inner peripheral surface 520 of the firstlubricating portion 52 is slidably in contact with the inner ringraceway surface 41 so as to lubricate the inner ring raceway surface 41.Further, the side surface 521 of the first lubricating portion 52 isslidably in contact with both the wall surfaces of the groove portion 42so as to lubricate the groove portion 42.

Further, the inner peripheral surface 530 of the second lubricatingportion 53 is slidably in contact with the outer peripheral surface ofthe collar portion 43 corresponding to the guide surface of the cage 34so as to lubricate the outer peripheral surface of the collar portion43. At this time, since the slight clearance 54 is formed between theinclined surface 40 of the engaging recess portion 50 and the backsurface 490 of the solid lubricating agent 49 opposing to the inclinedsurface 40, the solid lubricating agent 49 starts a revolving motionbehind the rotation of the cage 34 by a degree of the clearance 54.Accordingly, the back surface 490 of the solid lubricating agent 49 isslidably in contact with the rolling surface of the cylindrical roller36 in the downstream side of the solid lubricating agent 49 in therotating direction so as to lubricate the rolling surface of thecylindrical roller 36. In this case, when the solid lubricating agent 49lubricates the rolling surface of the cylindrical roller 36, the outerring rolling surface 37 is lubricated.

In the case that the lead-lag is generated in a part of a plurality ofcylindrical rollers 36, in accordance with the rotation of the innerring 33 around the axis 38, the cylindrical roller 36 is brought intocontact with the peripheral wall of the pocket 35 in the cage 34, sothat there is a case that the cage 34 is exposed to a compression forcein the peripheral direction particularly with respect to an adjacentcylindrical roller 36. However, as mentioned above, since the slightclearance 54 is provided between the inclined surface 40 of the engagingrecess portion 50 and the back surface 490 of the solid lubricatingagent 49 opposing to the inclined surface 40, no compression force isapplied to the solid lubricating agent 49. Accordingly, even if thelead-lag is generated in a part of the cylindrical rollers 36, aphenomenon that the solid lubricating agent 49 is broken away due to thelead-lag can be prevented.

Further, when the solid lubricating agent 49 revolves around the axis 38and is slidably in contact with both the wall surfaces of the grooveportion 42 and the inner peripheral surface of the collar portion 43 soas to lubricate, the height of the solid lubricating agent 49 in thediametrical direction is reduced step by step. However, since theinclined surface 40 is formed in the engaging recess portion 50, thesolid lubricating agent 49 is pressed to the inner side in thediametrical direction by the inclined surface 40, in accordance with therotation of the cage 34 around the axis 38. Accordingly, even in thecase that the height of the solid lubricating agent 49 in thediametrical direction is reduced, in accordance with the use, it ispossible to keep the operation that the solid lubricating agent 49 isslidably in contact with both the wall surfaces of the groove portion 42and the inner peripheral surface of the collar portion 43, in accordancewith the rotation of the cage 34 around the axis 38.

In the case of the rolling bearing mentioned above, the clearance 54 isprovided between the inclined surface 40 of the engaging recess portion50 in the cage 34, and the opposing surface of the back surface 490 ofthe solid lubricating agent 49 opposing to the inclined surface 40.Further, since the compression force caused by the lead-lag of thecylindrical roller 36 is supported by the cage 34, the compression forcecan be prevented from being applied to the solid lubricating agent 49.Accordingly, the solid lubricating agent 49 can be prevented from beingbroken away due to the lead-lag of the cylindrical roller 36 so as tolubricate the necessary surface.

Further, since the inclined surface 40 is formed in the engaging recessportion 50 of the cage 34, the solid lubricating agent 49 is pressed tothe inner side in the diametrical direction by the inclined surface 40,in accordance with the rotation of the cage 34 around the axis 38 evenin the case that the height of the solid lubricating agent 49 in thediametrical direction is reduced in correspondence to the working.Accordingly, it is possible to maintain the operation that the solidlubricating agent 49 is slidably in contact with both the wall surfacesof the groove portion 42 and the inner peripheral surface of the collarportion so as to lubricate, for a long period.

In this case, the present invention is not limited to the cylindricalroller serving as the rolling element, but can be applied to a rollingbearing using balls. In this case, in the same manner as mentionedabove, the engaging recess portion is formed in the outer side portionin the diametrical direction between the pockets in the cage for theballs or the inner side portion in the diametrical direction, and thesolid lubricating agent is attached to the engaging recess portion insuch a manner that the solid lubricating agent can move slightly in theperipheral direction, thereby lubricating a ball raceway surface. Inthis case, since the cage supports the compression force, in accordancewith the lead-lag of the ball, the bearing can be used for a long periodwithout breaking away the solid lubricating agent, and the racewaysurface can be lubricated.

The solid lubricating agent, in accordance with the present inventionmay be constituted by a solid lubricating agent, which can lubricate atleast the outer ring raceway surface or the inner ring raceway surfaceamong the outer ring raceway surface or the inner ring raceway surface,both the wall surfaces of the groove portion, and the guide surface ofthe cage in the collar portion. In this case, the solid lubricatingagent is structured such that the solid lubricating agent is attached tothe recess portion formed in the outer side portion of the cage in thediametrical direction or the inner side portion in the diametricaldirection and lubricates the outer ring raceway surface or the innerring raceway surface, in accordance with the rotation of the cage.

INDUSTRIAL APPLICABILITY

In accordance with the present invention, it is possible to apply to therolling bearing used under the high temperature and the high pressure.

1. A rolling bearing, comprising: an inner bearing ring; an outerbearing ring disposed radially outward of said inner bearing ring; acage arranged in an annular space between said inner and outer bearingrings, said cage including rolling element receiving pockets arranged ina circumferential direction, and further including recess portionsbetween the rolling element receiving pockets in the circumferentialdirection; rolling elements which are received in the rolling elementreceiving pockets; and at least one integrally formed solid lubricatingagent which is at least partially received in the recess portions so asto captively move along with the cage and be in slidable contact with arolling element raceway surface of one of said inner and outer bearingrings facing said cage.
 2. A rolling bearing as claimed in claim 1,wherein the at least one integrally formed solid lubricating agent has afirst lubricating portion, which is slidably in contact with saidraceway surface of said one of said inner and outer bearing rings, and asecond lubricating portion, which is slidably in contact with a guidesurface in a shoulder portion of said one of said inner and outerbearing rings.
 3. A rolling bearing as claimed in claim 1, furthercomprising an inclined surface which is disposed in the recess portionpressing the at least one integrally formed solid lubricating agent in adiametrical direction in accordance with a rotating motion of the cagearound the axis.
 4. A rolling bearing as claimed in claim 1, wherein thesolid lubricating agent is formed by a graphite.
 5. A rolling bearing asclaimed in claim 1, wherein the at least one integrally formed solidlubricating agent is engaged with the recess portion so as to bemoveable in a peripheral direction with respect to the cage.
 6. Arolling bearing as claimed in claim 5, wherein the at least oneintegrally formed solid lubricating agent is engaged with the recessportion so as to be slidably in contact with an adjacent one of therolling elements.
 7. A rolling bearing, comprising: an inner bearingring; an outer bearing ring disposed radially outward of said innerbearing ring forming an annular space therebetween; a cage arranged inthe annular space between said inner and outer bearing rings, said cagehaving a plurality of rolling element receiving pockets arranged in acircumferential direction, said cage further including recess portionsdisposed between the rolling element receiving pockets in thecircumferential direction, the recess portions each having a bottomsurface and a pair of inclined surfaces inclined so as to be expandedfrom both sides of the bottom portion in a circumferential direction andradially outward; a plurality of rolling elements received in therolling element receiving pockets in the cage; and at least oneintegrally formed solid lubricating agent being at least partiallyreceived in the recess portions in a state in which a back surfacethereof is opposed to the inclined surface of the recess portion with aclearance therebetween, said at least one integrally formed solidlubricant including a first lubricating portion detachably fitted to thegroove portion of the one bearing ring and a second lubricating portionbulged out to both sides of the first lubricating portion in the axialdirection so as to be loosely fitted to the recess portion when at leastpartially received therein, a one of said inner and outer bearing ringsincluding a groove portion forming a raceway surface of the rollingelement on an opposing surface to another one of said inner and outerbearing rings, and a shoulder portion for holding the rolling element inboth sides of the groove portion in an axial direction, both of saidfirst and second lubricating portions having a back surface in adownstream side of said one of said bearing rings in a rotationaldirection.